Cooling system for internal combustion engines



Nov. 16, 1965 o. MONTABONE 3,217,792

COOLING SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Oct. 29, 1963 United States Patent 3,217,792 COOLING SYSTEM FOR INTERNAL COMBUSTION ENGINES Oscar Montabone, Turin, Italy, assignor to Fiat Societa per Azioni, Turin, Italy Filed Oct. 29, 1963, Ser. No. 319,756 Claims priority, application Italy, Nov. 3, 1962,

21,946/ 62 1 Claim. (Cl. 165-73) This invention relates to cooling systems of the socalled sealed type for liquid-cooled internal combustion engines. a

As is well known in sealed cooling circuits a type of cooling liquid, which has antifreeze properties and considerable chemical inertia, is filled in at the time of manufacture of the car and need not be renewed for a long period of time (two to three years) which avoids the necessity for re-filling.

Such sealed cooling systems impose upon the designer special problems as compared with conventional nonsealed arrangements.

The sealed cooling systems of the prior art must have a minimum of leakage, and provide means for expansion of the cooling liquid, as well as for detecting any liquid leakage beyond a certain safety limit.

Such problems have been solved heretofore in various ways, essentially by using additional reservoirs freely connecting with the remainder of the system subjected to the variable pressures or to external atmosperhic pressure.

Since critical conditions may arise during operation of the engine, which may generate steam within the cooling system and tend to raise the pressure therein considerably, the arrangement should be either capable of withstanding such overpressure or be designed for operation at ambient pressure.

An object of this invention is to provide a sealed cooling system adapted to operate under the same conditions as a non-sealed conventional cooling system, that is, at a pressure generally exceeding ambient pressure but not exceeding a pre-determined value.

A further object of this invention is to provide a sealed cooling arrangement which is particularly safe against burst-outs, and which can easily be assembled by adding a few parts to an existing non-sealed system.

The sealed cooling arrangement according to this invention is of the type in which a deformable auxiliary liquid reservoir is connected to the cooling liquid circuit, and is characterized by the fact that communication between this reservoir and the liquid circuit is controlled by two valves, one opening when the pressure in the circuit exceeds the pressure in the reservoir and the other when the pressure in the reservoir exceeds the pressure in the circuit, respectively, the valves being set to operate at the highest and lowest value of normal operating pressure in the cooling circuit, respectively, the deformable reservoir being maintained substantially at ambient pressure.

The invention shall now be described with reference to the accompanying drawing which shows diagrammatically an embodiment thereof.

FIGURE 1 is a diagrammatical view of a liquid cooling system for an internal combustion engine;

FIGURE 2 is a part-sectional detail view on a larger scale of a portion shown in FIGURE 1; and

FIGURE 3 is a detail view of a modified embodiment of an auxiliary tank.

In FIGURES 1 and 2, 1 denotes an internal combustion engine, for motor vehicles, 2 the radiator of the cooling liquid for the engine, 3 and 4 the conduits connecting the bottom manifold 2b of the radiator with the 3,217,792 Patented Nov. 16, 1965 ice bottom engine portion and the top manifold 2a of the radiator with the top engine portion, respectively.

A cooling liquid circulating pump 5 is interposed in the bottom conduit 3.

The top manifold 2a of the radiator 2 is provided with two connecting fittings 6, 7 from which two conduits 8, 9 extend and connect through a common conduit 10 with a resiliently deformable reservoir 11 of substantially spherical shape.

A valve 12 is interposed in the connecting fitting 6 and is biased by a spring 13, a valve 14 biased by a spring 15 being interposed in the connecting fitting 7.

The valve 12 is adapted to control the flow from the manifold 2a to conduit 8, the spring 13 being set to cause the valve 12 to open when the pressure differential between the resilient reservoir 11 and manifold 2a is, for instance, of the order of 0.6 atm.

The valve 14 is adapted to control the flow from the conduit 9 to the manifold 2a, its respective spring 15 being set to cause said valve 14 to open by effect of a pressure differential such as 0.05 atm.

The deformable reservoir 11 is adequate in capacity compared to the liquid volume in the cooling system; for instance, its volume may equal 25% of the capacity of the cooling system.

The highest value of normal operating pressure in the circuit is adjusted by the valve 12 which permits part of the liquid to flow into the reservoir 11; on the other hand the minimum operating value is determined by the valve 14 which admits back flow of liquid into the circuit under atmospheric pressure acting on the reservoir.

Though the cooling circuit according to this invention is tightly sealed, any accidental liquid leakage is readily detected. On filling-in the liquid the resilient reservoir 11 receives a certain liquid quantity which is easily controllable from the outside by direct inspection, if the wall of the reservoir 1 is made transparent, or by checking inflation of the reservoir.

According to a modification a transparent level gauge 17 is arranged on the conduit 10 for checking purposes. The gauge 17 may be mounted on the instrument panel by means of flexible conduits.

Any leakage occurring during operation is compensated by liquid flowing from the resilient reservoir 11 to the radiator through the blackfiow valve 14 during the cooling stage. Emptying of the reservoir 11 is a warning of accidental leakage.

The reservoir 11 should be made of a flexible chemically inert material as far as the cooling liquid is concerned such as rubber or the plastics. The resiliency thereof advantageously assists the atmospheric pressure in causing liquid to flow back to the radiator even against a certain pressure gradient.

The reservoir 11 is provided with a relief valve 16 venting to the outside. The valve is set to open at a definite pressure such as 0.3 atm. The valve acts as a safety for the deformable reservoir 11 avoiding excessive stresses. The valve 16 is moreover adapted to act as a warning in case of damage, such as that of the seal of the engine head allowing flow of gas from the combustion chamber to the cooling circuit.

For this purpose the valve 16 may be connected to actuate a switch for a signalling lamp or an acoustic signal arranged within the vehicle. Obviously, the valve 16 is not in operation under normal conditions.

The modified embodiment in FIGURE 3 employs a cylindrical reservoir 18 provided with a piston 19 biased by a spring 20.

It is to be understood that the invention is not restricted to the precise constructional details set forth.

So, for instance, the valves 14 and 12 can be arranged co-axially instead of in the manner shown.

What I claim is:

A liquid cooled internal combustion engine including a cooling radiator of the sealed type, wherein an auxiliary reservoir containing part of the cooling liquid is connected by parallel conduit means to the cooling radiator of the engine, characterized in that said reservoir is of deformable resilient material and said parallel conduit means are each provided with a check valve, one of said check valves having bias means whereby it opens when the pressure in the circuit exceeds the pressure in the reservoir and the other of said check valves having bias means whereby it opens When the pressure in the reservoir exceeds the pressure in the circuit, the respective bias means being set to, operate at the highest and, lowest value of normal operating pressure in the cooling-circuit, said deformable reservoir being maintained substantially at ambient pressure.

References Cited by the Examiner UNITED STATES PATENTS 1,378,724 5/1921 Rushmore 137493.8 2,147,699 2/ 1939 Hardiman 16534 3,108,633 10/1963 Walton 23766 FOREIGN PATENTS 516,462 1/1953 Belgium.

592,656 2/1960 Canada. 1,226,713 2/1960 France.

JAMES W. WESTHAVER, Primary Examiner.

15 CHARLES SUKALO, FREDERICK L.

MATTESON, JR., Examiner. 

